Telephone central office switch



1No Model.) 2 Sheets-Sheet 1v M. J. CARNEY.

TELEPHONE OENTRAL OFFICE SWITGH.

No. 258,886. Patented June 6. 1882.

(No Model.)

M, J. CARNEY.

TELEPHONE GBNTRAL GPPIOB SWITCH.

Patented June 6. 1882.

Jaw, f8, C1A-m Ifrueno?" UNITED STATES PATENT OFFICE.

MARTIN J. OARNEY; OF TOLEDO, OHIO, ASSIGNOR OF ONDHALF TO JOHN M.lVllEliLEl, OF SAME PLACE.

' TELEPHONE CENTRAL-OFFICE SWITCH.

SPECIFICATION forming part of Letters Patent No. 258,886, dated June 6,18E2,

Application tiled October i4, i981. (No model.)

To all whom it mag/,concern Be it known that I, MARTiN J. CARNET, acitizen of' the United States, residing at Toledo, in the county ot'Lucas and State of Ohio, have invented certain new and usefulImprovements in Telephone Central-Ottico Switches; and I do herebydeclare the following to be a full, clear, and exact description ot' theinvention, such as will enable others skilled in the art to which io itappertains to make and use the satire.

The general object ot' my invention is to facilitate the work ofconnecting and discorrnecting subscribers litres at the centratofticeswitch, and to make it possible to do the necessary work with a lessnumber ol' operators and with less noise and confusion than has hithertobeen the case.

My invention relates more particularly tothatclassot'switch-boardsknownasscctional 2o boards, in which thesubscribers lines between which communication is most frequently desiredare assigned and connected to one ot' the sections ofthe switcl1,atrdthe work ot' receiving and sending calls and makingl connections betweenthe subscribers oi that section is done entirely upon that section oftheboard, while it' the subscriber of one section makes known to theoperator of his section that he desires communication willi thesubscriber ot' 3o some other section additional local signals andconnections between the two sections are brought into play, and the twosubscribers are placed in communication by suitable manipulation of bothsections ot' the switch by the two operators assigned to those sections.

The special object ot' my invention is to provide a. simple andeffective means, and one capableot' heilig put into a small compass,whereby the operator at any section ot' the switch 4o may place anysubscriber ot' that section in communication with thesubscriberot'anyother section without the assistance of other opera.-tors or attendants, at the saine time allowing the operations ot'connecting and disconnecting subscribers ofthe first-named section to beperformed in the ordinary way.

My invention consists in certain special coinbinations of supplementalline strips or plates and supplemental instrument and line con- 5onecting strips, which are stated in the claims,

and which will be more readily understood from the accompartying`description and drawings.

My invention also consists in a certain novel construclion of aswitchplug adapted t'or use 55 upon plug switch-boards.

In the accompanying drawings, Figure l is a diagram or plaitillustrating the circuits aml connections upon a telephone switch-boardot' sections, three of the lines only being shown 6o as connected, forthe sake of clearness. Fig. 2 showsa modification and illustrates auarrangement of the various portions of a board having a larger numberol' subscribers lilies connected thereto. Fig. 3 shows a longitudinal 65and an enlarged transverse section ot" an improved switch-plug, and anenlarged detail vertical section ot' tite lower portion thereof.

)teferring to Fig. l, A, B, and O represent thethreesrctionsof theboard,tocach ot' which 7o is connected a set of lines between whichcommunication is frequently desired. The annunciators t'or the litresproper of each section are located at their sections within view ot' theoperator having charge ot` thesection, and the calls t'roxn thesubscribers ot that section are received only by him.

The operation ot'conuccting the wires ot' any one section and ofsignallingI to subscribers upon those lines is performed in the ordinary8o way. Should an order be received from any subscribers for connectionwith a subscriber whose calls are received at any other section, thelatter is called by the operator otthe tirst subscriber, and the linesare connected at the section of the board to which the u'iic ot' thcsubscriber giving the order is connected. The special arrangement ot'circuits by which this is accomplished, and the special apparatuseinploycd for the purpose ot' giving eompactness 9o to the switch andot' putting` all the nii-es of even a very large switch within thecontrol ot' the operator ot' each section, will be now described.

Three main or principal line-strips of a plug switch-board arerepresented by the letter a in section A, by b in section B, and by c insection C. Each of these line-strips is connected to one of the lines ofthe section to which it belongs, and from each line strip the loocircuit is to eartll through all anllunciator of any desired kind,located at the section of board to which the lille is immediately co1-nected, alld plates d, joined by plug-conllections, as indicated, with aplate connected to earth.

Illclnded ill the circuits ot' the various lillesirips alld theground-plate are supplemental line plates or strips located ill theother sectionsoftheal paratus. Tllesupplenlentallillestrips throughwllicll the lille circuits for section A pass are shown ill section llat the slipplelllelltal section A Il, and ill section C at A c.Similarly the supplemental boards or sectiolls in sections A and C,through which the lilles of' sectioll B pass, are indicated at B u and Bc, respectively, alld tllose ill A and B, for the lines ot' C, by C uand C b, respectively. Taking, for illstallee, the lel't llalld lille,orlille 1, of section A` its circuit is as follows: Entering itslinestrip a, the circllit is tllrollgh a plug alld terlllinal plate,f,to a supplemental line strip or plate, g, ill ll section of the board,through a tel nlillal plug alld switch-plate, h, to a supplelllentalline-strip, I, ill section C of the board, tllrougll a terminal plateand plug, as shown, for said plate; thence ill reverse order through aplate, i', alld a plug and plate, lr, ill section C, and similar platesand plugs ill section B, to all annunciator, D, a plate, d, ill sectionA, and to a plug and plate connected to earth. In a silnilar manner linelill section B is connected through a correspondingly-numberedsupplemental lille-strip, nl, of section A, a supplemelltal lille-strip,i, in supplemental seetioll B c of section C ot' the board, and illreverse order through the plates ot' sections C alld A, alld to groulldat section B, first passing through an annunciator. By tracing thecollneclion from C it will be observed that lille 1 ot' that section isalso connected to ground through correspolldillg supplementallille-strips ill C b and C a, alld ill reverse order through theircorresponding plates and plugs, i il". Similarly all the other lillesill each section are taken to earth through colrespolldillgly-llulnberedsupplemental plates ill all thc other sections alld through the properplates `l' 7l' of those sections ill reverse order.

E and F represellt principal line-connecting strips in eacll section ofthe apparatus, said strips being adapted to connect any two ofthelille-strips u a or b l by the insertion of collnectillg plugs ill thewell-known manner, or to be connected to any lille-strip separately.

E and F' represent supplemental connectillg-stripsjoined to theprincipal line-connecting strips in eacll section, and adapted to beconnected with any one of the supplemental line-strips g, l, and `m illthe various sections.

K K K represent instrument strips or plates, one for the principal boardot' each section, to which are joined telephone communicating alldsignaling apparatus of any desired kind, consisting of a reeeiviug-telephoue, T, batterytransmitter M, and magneto generator N forsending signaling-currents, the latter being provided with anorlllally-closed shuntillg-key, P, which may be constructed ill anysuitable manner, so as wllell depressed to break the short circuitaround the generator, tllus callsing its currents to be sent to lille.

Supplementalillstrlllllellt-strips lt,connected with the maillinstrument-stlips K,extend over the vertical series of plates i ill thesupplemental portions ot' the various sections, alld may be connectldwitll any one ot' the plates 'i by the insertion ot'aplllg, which, illthe proper operation ot' the switcll, should be thc plug connectingplates i alld lr, so that ill the actot' connecting the signalingapparatus ot any section t0 a supplemental lille-plate and to the lillebelonging to some other sectioll the dropalluullciator ot' the lattersection alld the plate through which thatline lllay be connected withits lllaill or principal instrulllent-stlip, as well as the plate `i ot'intermediate supplemental boards, will be disconnected. By this meansthe allllllllciator ot' that section is not affected, and, moreover, itis ilnpossible for the operators at the lnaill orprillcipal section andat thc intermediate sections to create confusion by attempting to signalat the same time that a signal is heilig sellt from the supplementalillstrulnellt-strip of some other section.

By the above constrllctioll the operator ot each sectioll can, throughthe supplemental instrument-strip l, send a call to the lille propel'ot' any other section, since, as has been described, the lille-circllitt'or every wire of every other section passes to earth through asupplemental plate and plug, t lr, ill all others. He can also collllcctany wire upon his lnaill or principal board with the wire ot ally othersection of the board through either of the slipplelnelltallille-connecting strips E 1t", the latter being colullloll io thesupplemental lillestrips of the section, alld the supplementallille-strips themselves representing alld being connected with thclille-wires ot all other sections. Moreover, this portion ot' theapparatus can be put ill slllall compass, as the instrument andlille-connecting strips are continuous strips, and are colnllloll to allthe plates l', alld the supplemental lille strips ot' any one sectioll,while the plates 'i and the sllpplelllelltal lille-strips can be lnadeot' very slllall dilllellsions, the length necessary for the latterbeillg only that which will bc slltlicient to accommodate the maximumnumber ot' supplemental line-connectillg strips required. Under ordinarycircumstances the number of the latter would be but few.

The operatioll of the apparatus is as follows: If a call be receivedfrom a subseliberof lille 1,sectioll A, the anllullciator ot' that linewould indicate the fact to the operator of that section, the path ofthecurrent tothe annunciator beill g, as before described, throughsllpplcmental line-strips ill sections B and C, and in reverse orderthrough corresponding plates, i 1f. The operator would tllereupollconnect the IOO telephone apparatus MT with tllat line by removingtheplug from ground connection plate d and inserting it illinstrument-strip K, thus connecting the latter to plate d alld to thelille through the supplemental lille-strips of the other sections. Ifthe call be for a subscriber in the same sectioll, that subscriber wouldbe called by connecting the plate d of that lille to theinstrument-strip K, and the signal would be given in the ordinary way bythe magnetomachine, the short circuit ot' the latter being broken by thepnsh-button P to cause its cnrrents to tlow to lille. Should that lillebe already ill use at the supplemental hoard ot' soule other scctioll,tllat fact wollld be made known to the operator by the absence of noisecaused by the currents from the machine ill his receiver T, this beingduc to the severing of the line-circuitin some other board attlle pointik or at the terminal plate l, ill the manner to be presently described.The signal having becll given, the lilles would be connected in theordillary way by the insertion et' plugs in one ofthe line-connectingstrips E F. In performing this operation the plug connecting thetwolinestripswitll thel terminal platesfsllould be withdrawn, so as tobreak the connection ofthe lines to the supplelllelltal lille stripsalld collncctioll-plates `l' ot' other sections, thus male ing itimpossible for the operators of other sections to signal to the lillcswhile connected. rllhe operatioll ot' collllecting a line ot' sectioll Ato a lille of section B would be as follows: Tile call having beenreceived ill the ordinary way, the operator at A would proceed to conneet his instrumentstrip witll the desired lille ot' section B by makingplug-connection between llls supplenlental instrument-strip Rand theplate'l, tllrollgll wllicll the circuit of thelillc desired passes. Letit be supposed that lille 1 of section B is the lille with wllichcommuni catioll is desired, and tllat the plug connecting plates `i hot' that line upon supplemental board B a has been witlldrawn andinserted in strip lt, so as to colllleet the latter with the plate i.The circuit from the signaling apparatus of A would then be throughillstrnmellt-strip K ot' section A, supplemental strip 1t, platel oflille 1 ill supplemental scctioll B a, plates k -l' ot' lille 1,supplemental sectioll B c, terminal plate h alld supplementallille-strip l ill that scctioll,

terminal plate h and supplemental line-strip nl, lille 1 of supplementalsection B (l, tllenee directly to principal lille-strip b, lille 1 ofscction B, through its terminal connecting-plate, alld to subscribelsline 1 of section B.

At the saule time, by the removal of the plug connecting` plates i 7l'in section B u, the collllectioll otl the lille with its anuuneiator andplate d under instrument-strip K ill main seetion B would have beenbroken, so that the act of si gnaling froln section A to the line wouldnot give a false signal upon the anllunciator of section B, and theoperator ot' section B would also be prevented from signaling the lineat the same time through K and dof section B, annunciator, and plates 7;i ot' supple mental section B a, Sec. Lilie 1, section B, having beencalled, the two lilies would be connected by withdrawing the terlllinalplug couneeting plate m, lille l, section B al, with its terminal plateIl, and inserting it ill one of the supplemental lille-strips E F', theterminal connectingplug at fof principal line-strip a, line 1, sectionA, having been also withdrawn and inserted in the correspondingline-colluccting strip, E or F. The removal ofthe plug at h would securethe two connected lines trom interruption from other sections ot' theapparatas by breaking the connection of supplemental line-stripm withstrip I, plates 'i k,and instrument-stlip Rot'supplelnental sectioll Bc, and with plates l' lr, section B u, and the plate d forinstrulnellt-strip K of lnaill seetioll B. In a simil-.lr lnallller therenlovalof the plug atf, lille l, section A, would prevclltillterruptioll by an attempt to signal to that line from supplementalsections Ab alld A cof sections B alld (l, as can readily be seen byfollowing the circuits. r1`llc want of continuity ill the two linecircuit connections at fand Il would also make known to the operators atB and C that the lines welc ill use,since ill this case on attempting tosend the signal no sound would be heard ill the receiver T.

From the above it will readily be seen that when a lille is in use,eitllerllpoll the principal board or upon the supplemental board ot' anysection, interruption from ally other section callllot take place. Forinstance, it` lille 1, sectioll (l, be ill ilse upon the lllaill orprincipal board, the removal of the plllg atf, which is dolle t'ol' thepurpose of connecting the line strip to the line-connecting strip willcut oft' the supplemental boards U b alld U u.. If that lille be ill useat board C b, the rellloval of the plug at Il, which is used forconnecting the supplemental lille-strip to the supplementallillceconllecting stlip, will cnt ott the supplenlelltal board U a andthe signaling alld colllnlunicating apparatus at C. In the sallle way itwould be impossible for operator at section A to signal to linc 1assigned to his board it that lille bc collllected by nlcans of theslip- IOC IIO

plelnental lille-plate and lille-connecting stripes: l5

upon some other section with a lllaill or prillcipal lille ot' thelatter, since the continuity of the circuit from his illstrunlent-stlipK and collllectcd plate d to lille 1 wollld be broken at one ot' thepoints Il ill a supplemental section. I have not here shown any specialdevices for giving a signal i'or disconnection to the central oiiicefrom connected subscribers, since various devices may be. used for thispurposeas, t'or instance, the well-known device ot" a high-resistanceilldicatorcollnected ill a. brallell to ground from the lilleconnectingstrip.

lt`desircd, the eall-annunciators for the lilies might be placed betweenthe lille and the switch-board, so that when two lines are conneeted theanllullciators would be between them. 1u this ease, however, the act ofsig- .1 Masse naling from the supplemental switch-board of one sectionto the line proper ot' another section would operate the anuunciator,and thus give rise to confusion.

lf desirable, the plates i may he placed at one side of the strips 1tinstead of beneath them, as shown, although foreotnpaetness the latterplan is preferable.

In the moditied arrangement shown in Fig. 2 five line-strips are sllownin each ofthe three main sections A B C, and the two supplemental boardsor sections are ranged side b v side instead ot vertically one above theother. The latter plan renders it necessary to duplicate thesupplemental instrument-strips and the supplementalline-connectingstrips. Both suppleinental line-connecting strips in eachmain section are, however, connected with the sa me principalline-connecting strip, and the two supplemental instrument-strips arealso connected to the same principal instrument-strip. The generalarrangement and connections are iu other respects substantially the sameas in Fig. l.

When a switch is divided into a large number of sections it may benecessary to arrange three or more supplementalsections inthe samehorizontal linc,other sections being placed vertically beneath theothers to any desired numher, to be determined by the circumstances ofthe case. The various line-connecting and instrument strips in the samevertical line would preferably be made continuons. Other dispositionsot' the various sections will readily suggest themselves to thoseskilled in the art. In the practical construction of the switch thesupplemental line-stri ps could be made ol' very small dimensions, andno dilliculty would be lound in bringingall thelinesof thclargestexchange within the control of each operator l'or thepurposeofsignalingto any lineand making the desired connection between any twolines, calls being received by each operator only from the linesassigned to his section.

It will be readily seen from the foregoing description that it is noteven necessary to place the various sections of the apparatus in thesame room, and that, it' necessary, they may be placed in differentrooms, or even in different buildings.

The improved switch-plug shown in Fig. 3 consists of a stem or spindle,5, reduced in diameter at its middle portion, and having se cured at itslower end in any suitable manner two semi-cylindrical springs, 44,whichmay he either constructed separately and secured by screws lo the lowerend of the stem, or may be cast in one piece with the enlargement at thelower end of the stem, the reduced portion of the stem being constructedseparately and afterward screwed into the enlarged portion. As thusconstructed the plug insures good connection between the upper and underplates of the board, since the end ot' theplugis seated firmly in thesocket in the lower plate, while the springs make iirm contact with theedges ot' the opening in the upper plate.

What I claim as new, and desire to secure by Letters latent, is-

1. The combination, in each section of a scctional telephoneswitch-board, of linestrips or plates connected to the lines assigned tothat section, connecting strips or plates adapted to be connected tosaid line-strips, a series of supplemental line-strips interposed in thecircuit ot the lines assigned to and connected with line-strips onanother section of the apparatus, and a connecting-strip com mon to saidsupplemental strips, and with which any one ot said supplemental stripsmay be connected, said latter connecting-strip being joined to the plateor strip which is adapted to malte connection with principal line stripsor plates ot' the tirst-named section.

2. A sectional telephone switch-hoard each section ot' which contains aset of principal line-strips and means for connecting any twoline-strips for oral connnunication, one or more sets of supplementalline-strips, the number of said sets being one less than the wholenumher ot' sections, each of said line-strips formA ing a portion ot' aloop from a principal lillestrip and the ground connection plate ofanother section, supplemental connecting-strips connected with theprincipal line-strips of the sectiomand a supplemental instrument-stripadapted to he connected with the loop at a point between the varioussupplemental linestrips and the ground connection platein which saidloop terminates.

3. 'l`he combination, with the principal lincstrips and the groundconnection plates of one section of a sectional switch-board, ofleadingwires connected to said line-strip and containing correspondingsupplemental line-strips in another section, return-wires connected tothe ground-plates, connecting-plates and switchpl ugs normallyinterposed in said return-wires, and a supplementalinstrument-stripcombiued with said connccting-plates,the whole arrangedin the manner described, s0 thatwheu any one of said plugs is shifted tothe instru ment-strip the connection ot' a return-wire with anormally-connected ground-plate is broken, and connection is at the sametime made between the instrument-strip and a principal line-strip ot'the tirst-namcd section.

4. The combination, with the principal lincstrip in one section ot'asectional switch-board, of a leading-win passing through supplementalline-strips in the other sections, a return-wire adapted to be conuected with a supplemental instrument-strip in each of said sections,switchplugs normally forming a part of the leadingwire, as described,and supplemental connecting-strips, the whole combined in the mannerdescribed, so that said plugs may be removed and used for connecting asupplemental lineconnecting strip with a supplemental line-strip, and sothat at the same time the continuity ot' the leading and return wirewill be broken and the use of the supplemental instrumentistrips inother sections for sending signals be prevented.

5. The combination, in each section ota sectional switch-board, of mainor principal linestrips and connecting devices adapted to connect anyot' the lines assigned to that section, one or more sets of supplementallinestrips, the strips in each set being connected in local circuits orloops leading from the corresponding principal line-strips of anothersection or sections and terminating in the groundconnecting plates ofthat section or sections, and connecting-strips joined to the principalconnecting devices ofthe first-named section, and adapted to makeconnection with the supplemental 1ine-strips in the latter section, allcombined in the manner and for the purposes set forth.

(i. The combination, in each section oi' a sectional switch-board, ofline-connecting and iu dicating devices for the lines assigned to thatsection, signaling and communicating apparatus adapted to be placed inconnection with any one ot' said lines, a series ot supplemental platesplaced in the circuit of lines assigned to another section of theswitch-board, and interposed between the line strips or plates and theground-plates of that section, an instrument strip or plate common tosaid series ot' supplemental plates and connected to the signalingapparatus ot the section in which said plates are located, andswitch-connecting plugs forming a portion of and adapted to preserve thecontinuity ot' the loops or connections in which the piates are normallyconnected, or to counect said plates to the instrumentstrip, at the sametime breaking the normal connection.

'7. The combination, with a sectional telcphone switch-board apparatus,in which the line circuits for each section pass to and throughsupplemental devices in the other sections, of anuunciators for eachsection, placed in circuit between the earth and the supplementaldeviees of other sections, so that when connection is made with saidcircuit upon the supplemental portion of other sections for the purposeof signaling to a subscriber-s station from such other sections theannunciator at the central oilicc may be cut out and a false signal atthe section of board to which the annnnciator belongs be prevented.

8. A switch-plug consisting of a stem or spindle having attached to itslower end two semi-cylindrical springs embracing the stem and free attheir upper ends, substantially as described.

In testimony whereof I attix my signature in presence of two witnesses.

MARTIN J. CAltNEY.

Witnesses BFNJ. TnoMPsoN, H. C. TowNsEND.

